Closure of potassium M-channels by muscarinic acetylcholine-receptor stimulants requires a diffusible messenger
- 23 November 1992
- journal article
- Published by The Royal Society in Proceedings Of The Royal Society B-Biological Sciences
- Vol. 250 (1328), 119-125
- https://doi.org/10.1098/rspb.1992.0139
Abstract
The M-current (IK(M)) is a slow voltage-gated K+ current which can be inhibited by muscarinic acetylcholine-receptor (mAChR) agonists. In the present experiments we have tested whether this inhibition results from a local (membrane-delimited) interaction between the receptor and adjacent channels, or whether channel closure is mediated by a diffusible messenger. To do this, single Km+-channel currents were recorded from membrane patches in dissociated rat superior cervical sympathetic neurons by using cell-attached patch electrodes. Channel activity was inhibited when muscarine was applied to the cell membrane outside the patch but persisted when channels were exposed to muscarine added to the pipette solution. We conclude that a diffusible molecule (or molecules) is (are) required to induce intrapatch channel closure following activation of extra-patch receptors.Keywords
This publication has 25 references indexed in Scilit:
- A diffusible second messenger mediates one of the pathways coupling receptors to calcium channels in rat sympathetic neuronsNeuron, 1991
- Muscarinic suppression of the M-current is mediated by a rise in internal Ca2+ concentrationNeuron, 1991
- On the transduction mechanism for muscarine‐induced inhibition of M‐current in cultured rat sympathetic neurones.The Journal of Physiology, 1989
- Classification of muscarinic responses in hippocampus in terms of receptor subtypes and second-messenger systems: electrophysiological studies in vitroJournal of Neuroscience, 1988
- M-currents: an updateTrends in Neurosciences, 1988
- Two polyphosphatidylinositide metabolites control two K+ currents in a neuronal cellNature, 1986
- Blockade of Ca‐activated K conductance by apamin in rat sympathetic neuronesBritish Journal of Pharmacology, 1986
- Functional innervation of cultured hippocampal neurones by cholinergic afferents from co-cultured septal explantsNature, 1985
- M‐currents and other potassium currents in bullfrog sympathetic neuronesThe Journal of Physiology, 1982
- Muscarinic suppression of a novel voltage-sensitive K+ current in a vertebrate neuroneNature, 1980